Menthol-release compounds

ABSTRACT

This invention relates to novel oligomers and polymers produced from monomer carbonate esters of menthol having the formula:   Wherein: N 0 to 8 R and R1 are independently selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons These compounds find particular use as methanol-release agents which will impart improved aroma, flavor, and taste effects to natural and reconstituted smoking products.

United States Patent [1 1 Rundberg, Jr. et a1,

[11] 3,887,603 June 3, 1975 MENTHOL-RELEASE COMPOUNDS [75] Inventors: Eric G. S. Rundberg, Jr.; William R.

Johnson, Jr.; Harvey J. Grubbs, all of Richmond, Va.

[73] Assignee: Philip Morris Incorporated, New

York, NY.

[22] Filed: July 30, 1973 [21] Appl. No.: 384,048

[52] U.S. Cl 260/463; 131/17; 260/618 R;

260/638 R [51] Int. Cl.... C08g 17/13; A24b 3/12; A24b 13/00 [58] Field of Search 260/463 [56] References Cited UNITED STATES PATENTS 3,419,543 12/1968 Mold et a1. 260/234 Primary Examiner-Donald G. Daus Assistant Examiner-Diana G. Rivers [57] ABSTRACT This invention relates to novel oligomers and polymers produced from monomer carbonate esters of menthol having the formula:

R and R are independently selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons These compounds find particular use as methanol-release agents which will impart improved aroma, flavor, and taste effects to natural and reconstituted smoking products.

9 Claims, No Drawings MENTHOL-RELEASE COMPOUNDS BACKGROUND OF THE INVENTION The addition of menthol per se to tobacco has been found to be ineffective. The highly volatile nature of this compound results in a relatively high loss factor incident to the storage and manufacturing stages required for the production of a smoking product. Quite clearly, such loss is undesirable from an economic standpoint.

In an attempt to alleviate these problems, it has been suggested that menthol might be absorbed on a suitable support, such as activated charcoal or fullers earth, and that the resultant composition might then be added to the tobacco. Attempts to pursue this method have not, however, met with complete success. The menthol yields from such adsorbants have been found to be very low. Moreover, this method obviously necessitates incorporation of the adsorbant into the tobacco, and such a foreign material may result in an undesirable appearance as well as give rise to uneven burning of the tobacco.

In order to overcome these difficulties, it has been suggested that the menthol could be incorporated into the tobacco as a part of a compound i.e. a menthol release agent in such form that upon burning of the tobacco, the compound would be decomposed to yield the desired menthol flavorant. While considerably more satisfactory than earlier attempts, even this technique has evidenced certain drawbacks.

Bavley et al, U.S. Letters Pat. No. 3,312,226, describes a process whereby menthol is incorporated into tobacco as the carbonate ester of various alcohols, particularly one such as linalool, which were themselves useful flavorants. Upon pyrolysis of these carbonate esters, incident to the normal burning temperatures of the tobacco, the menthol is released to flavor the smoke.

Unfortunately, these simple carbonate esters have not proven wholly satisfactory. They retain one of the difficulties of menthol itself, in that they are somewhat susceptible to migration in the tobacco, and thereby prevent the strict control of quantitative release of menthol to the tobacco smoke during burning. Additionally, the second alcohol of the carbonate ester can prove susceptible to chemical alteration during pyrolysis, thus giving rise to undesirable chemical fragments which may .add a chemical aftertaste to the smoke.

The Mold et a1 U.S. Pat. Nos. 3,332,428 and 3,419,543, offer a slightly different approach to the problem of adding menthol flavor to a tobacco smoke. These patents, like that of Bavley et al, rely upon the formation of a carbonate ester to bind the menthol in a release agent. Here, however, a polyhydroxy compound such as a monosaccharide, disaccharide, trisaccharide, polysaccharide, or glycol is used to fix the menthol in the tobacco. Again there are certain drawbacks.

Because the alcohol linkages of these saccharides and glycols are only primary or secondary in character, the efficiency with which the menthol can be regenerated upon pyrolysis is limited, owing to the opportunity for dehydration of the menthol moiety. Additionally, where attempts were made to utilize menthol-release agents of high menthol proportion i.e., agents which would release a high proportion of menthol per unit weight it was discovered the menthenes were often produced in addition to menthol elimination, thereby resulting in a bitter tasting tobacco smoke.

THE INVENTION It is the object of this invention to permit the incorporation into tobacco of a compound which will release menthol to the tobacco smoke.

It is a further object of the present invention to utilize a menthol-release compound characterized by a substantial lack of volatility and/or mobility at ambient temperatures within a tobacco composition. Such properties insure the uniformity of the flavor of tobacco smoke both within each individual tobacco product and from product to product.

It is a further object of the present invention to insure that any non-menthol residue resultant from the pyrolysis, incident to normal smoking, of a composition containing a menthol-release agent will be non-deleterious to the flavor of the resultant tobacco smoke.

It is a still further object of the present invention to provide a menthol-release agent for tobacco smoking compositions, characterized by an optimal efficiency of release of menthol, incident to normal smoking of the compositions. In this manner, the amounts of such additive required to be added to a tobacco composition may be minimized.

The objects of the present invention have been satisfied by the discovery of oligomers and lower molecular weight polymers which are characterized by repeating units of the formula:

u l l -c-o-c-(cn on Wherein:

N 0 to 8 M 2 to and R and R for each unit are selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons A preferred class of additive of this invention which maximizes the weight percent of menthol available for release includes those oligomers and lower molecular weight polymers which are prepared solely from monomers or mixtures of monomers selected from the lmenthyl l,l-dimethyl-alkenyl carbonates as are more fully described below.

The present oligomers and polymers cannot here be precisely identified individually in view of their occurrence as mixtures; possible minor rearrangements in the units incident to polymerization; and other variables with which those of ordinary skill in the art are I 3 v familiar. Based upon some experience and testing, however, it is believed that the additives of this invention may be characterized by the following molecular formula: 1

O ll -c--p- (cu 1 CH2 Wherein:

N =0 to 8 N 0 to 8 N 0 to 8 M 0 to 98 and The N value of each of the M separate internal units is independently variable within the values, 0 to 8. and

R, R, R, R and each R and R is selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons.

The addition of from about 1.0 to about 10.0 weight percent of members of the above-indicated classes of polymers to a natural or reconstituted tobacco smoking product will result, through the pyrolysis of the polymers under smoking conditions, in the addition of an appropriate amount of menthol to the tobacco smoke to meet the subjective demands of educated consumers. Such flavoration of the tobacco smoke results in the modifications of taste and flavor, so as to result in a gentle cooling effect on the mouth and throat and in a spice-like cooling and taste effect which will linger on after each puff.

It is believed that the instant production of menthol during smoking takes place in accordance with a simple pyrolysis reaction; the byproducts of which consist essentially of only carbon dioxide and an ordinary, nongaseous hydrocarbon. Accordingly, only the menthol itself is consequential with respect to flavoring the tobacco smoke, and one of the major drawbacks of the prior art additives thereby is avoided.

It has additionally been discovered that incident to the present use of a tertiaryalcohol ester attachment of the menthyl carbonates to the hydrocarbon backbone in the present polymeric menthol-release agent, the efficiency of menthol release is improved. The present esterificatiori the greatly preferred decomposition mechanism under ordinary smoking conditions. Accordingly, this invention. offers not only a method whereby substantially all the incorp' ated menthol may be released to the tobacco smok., out further does so in such manner as to result almost exclusively in the desired menthol product.

In addition to the aforementioned ease and selectivity of production of menthol, the instant oligomers and low molecular weight polymers are further characterized by their substantial lack of volatility and/or mobility within tobacco at temperatures beneath those encountered upon combustion of the smoking composition. Accordingly, the use of the present polymeric menthol-release agents avoids the pitfalls encountered in the processing and storage of tobacco products containing prior art flavoring agents.

In accordance with this invention, there are substantially no losses of menthol through sublimation or volatilization thereof during the manufacturing and storage operations incident to the production of a useful smoking composition. Additionally, the drawbacks of diffusion of menthol, or of a menthol-release agent, within the tobacco are successfully eliminated, and the control of quality and uniformity within the product tobacco compositions is successfully maintained.

The present polymeric menthol release agent may be produced from monomers having the formula:

Such compounds, per se, also constitute an important part of the present invention, although their production may be accomplished by means within the skill in the art, see for example Bavley et al, U.S. Pat. No. 3,312,226.

In the foregoing formula, the values represented by N, R", and R may be varied considerably without substantial adverse effect on the utility of the present monomers or of their product menthol release agents. Thus, for example, N which merely reflects the linear separation between the menthol releasing radical and the eventual polymeric backbone of the release agent should usually be maintained within the limits of from O to about 8 carbons in length, although most preferably this value resides between 0 and 2.

The side chains of the present monomers (R and R) and of the eventual polymeric release agent (R and R, or R, R R R etc. where mixtures of monomers are polymerized) may also be varied within wide limits without detrimental effect. As has been noted previously, each of these side chains must minimally comprise at least one carbon, in order to satisfy the discovered requirement that the carbon to which each pair is commonly attached in each monomer betertiary. The maximum size of the hydrocarbon side chains, on the other hand, is limited essentially through the steric effects of their presence in each monomer. They may therefore be selected in accordance with parameters well known in the prior art. Preferably, however, each such side chain should not exceed about 10 carbons in number.

Representative of the side chains which have been discovered to be useful in the present invention are the aliphatic, alicyclic and aromatic hydrocarbons. The most preferred of the aliphatic radicals are chains of l to 6 carbons in length, which may comprise either normal or branched aliphatics such as the methyl, ethyl, propyl and isopropyl moieties. Preferred alicyclics contain from about 5 to carbons and include the cyclohexyl moiety and lower (e.g. methyl and ethyl) homologs thereof. The most preferred of the aromatic side chains of this invention contain from 6 to 10 carbons and are exemplified by the phenyl, benzyl, tolyl and lower (e.g. phenyl ethyl and phenyl propyl) homologs thereof.

In order to avoid interference or complications during the polymerization of the present invention, the side chains should preferably be restricted to groups which will not enter into the reaction. Accordingly, it is desirable that the side chains comprise only saturated or aromatic constituents.

Preferentially, the synthesis of monomers and polymers within the scope of the instant invention is performed in accordance with the following sequence of equations:

hol. After a few minutes, the reaction mixture may be brought to room temperature and the metal alkoxide, if desired, isolated.

Equation No. 3 illustrates the preparation of the lmenthyl 1,1-substituted alkenyl carbonate monomers of the present invention. This synthesis may be accomplished through the addition of the l-menthyl chloroformate produced in accordance with Equation 1 to a solution of the metal alkoxide product of Equation 2. Both ingredients should be in appropriate solvents, for example anhydrous tetrahydrofuran, and the addition should be performed at close to ice temperature. The resultant admixture should then be heated at reflux temperatures (60 to 80C) for from 10 to hours, cooled to ice temperature, and then slowly hydrolyzed with water. Separation of layers is followed by extraction of the aqueous layer with anhydrous ether. Washing of the combined organic layers, followed by drying and solvent evaporation will yield the desired product as a liquid residue.

The vinyl unsaturation of the present monomers permits homopolymerization in the presence of conventional initiators of vinyl polymerization e.g. perox- OLi l 2 CH =CH- CH C 2 R L1 cn cu (CH ca 1 l R R wherein:

R may be alkyl (e.g. CH. C l-l n-C H n-Cd-l etc.) or aryl (e.g. C 11 (3) OLi l ot z-cl CH =CH-(CH CR Monomer (4) Monomer (B) Polymer (A) Equation 1 illustrates the preparation of a halocarides (preferably benzoyl peroxide) azo compounds and bonate which can be employed in accordance with the present invention. The reaction may, for example, be carried out at a temperature of from about 5 to about 35C in a common solvent for the menthol and carbonyl chloride e.g. benzene. The carbonyl chloride is preferably added in substantial molar excess of the menthol, and an appropriate catalyst e.g. pyridine may be employed in such an amount as to facilitate the reaction. The reaction mass should be stirred for a total of about 3 hours and then allowed to stand overnight. At the end of this time, l-menthyl chloroformate may be recovered as a slightly yellow liquid.

Equation No. 2 merely illustrates the activation of the unsaturated tertiary alcohol which will eventually constitute the backbone of the present polymeric mentholrelejase agent. The production of the metal alkoxide may best be accomplished through the addition, at ice temperatures and under an inert atmosphere, of approximately 111 proportions of a lower alkyl lithium compound to an appropriate, unsaturated tertiary alcothe like in accordance with the reaction set forth in Equation 4. The reaction of this equation may be performed at ambient temperature, but preferably from 50 to C, under an inert atmosphere. After from 20 to hours, the reaction mass may be dissolved in an appropriate solvent, washed and separated.

The present polymeric, menthol-release agents may vary greatly in molecular weight. Thus, for example, the number of monomeric units may range from 2 to 100 yielding molecular weights of from about 550 to 30,000. All such polymers are useful within the scope of this invention, however, it is preferred that polymerization be controlled through modification of the catalyst concentration, temperature, time of reaction, etc. in order to obtain reaction products having from about 6 to about 40 monomeric units or molecular weights of from about 1600 to about 12,000.

The product, polymeric menthol-release agent, may be incorporated into the tobacco in accordance with any of the methods customary in the art. Thus, it is possible merely to mix the polymer with the free tobacco prior to the manufacture of the product smoking composition.

Preferably, however, the polymer will be dissolved in an appropriate solvent such as acetone and then sprayed or injected into free tobacco. Such method insures a proper distribution of the polymer throughout the tobacco itself, and thereby permits the production of a more uniform smoking composition.

In the foregoing discussion, it is understood that in the various formulae the figure,

has been employed to represent the 2-isopropyl 5- methyl cyclohexyl radical. Additionally an unsatisfied valence in a formula such as polymer (A) merely indicates the position for similar attachment to another monomer or to a chain terminator such as a methyl radical.

Specific examples of the preparation of the present monomers and polymers, as well as of their use in a smoking product, are as follows:

EXAMPLE 1 Preparation of the Monomer A solution of 2-methylbut-3-en-2-ol (0.2 mole, l7.2g) in anhydrous tetrahydrofuran (Tl-IF, 300 ml) was degassed with nitrogen and cooled to ice temperature. n-Butyllithium (0.23 mole, 2.38M, 100 ml in hexane) was added to the icecold stirred solution during 8 minutes and a slow evolution of butane was observed. The reaction mixture was stirred at room temperature (27C) for 2 hours (gas evolution stopped by this time). After cooling the mixture to ice temperature l-menthyl chloroformate (438g, 0.2 mole) in anhydrous THE (150 ml) was added over a l4-minute period. The solution changed from a yellow to an orange-red color. The solution was heated at reflux temperature (65C) for 1.5 hours, cooled to ice temperature and slowly hydrolyzed with water (400 ml). The aqueous layer was washed with two volumes each of 75 ml and then 100 ml of anhydrous ether. The combined organic layers were dried over anhydrous Na SO for 16 hours. After filtration and solvent evaporation, an orangered liquid residue was obtained. A number of gas chromatographs were taken of the residue and a peak (menthol) increased as the injection port temperature gas was increased. The, residue was fractionally distilled through a spinning-band column and 4 fractions were obtained. An lR spectrum was taken of each fraction. (See below.)

Yield Yield EXAMPLE 2 Polymerization Benzoyl peroxide (BPO, 0.5g) was placed in a 100 m round bottom flask which was purged with nitrogen for 15 minutes. l-menthyl l,l-dimethylallyl carbonate (1 1.05g) was added via a syringe to the BPO while the system was flushed with nitrogen. The stoppered suspension (light yellow) was placed in an oven at i 2C. The mixture was swirled at 30 minutes intervals for 1.5 hours, and the BPO dissolved within 1 hour. After the mixture had been in the oven for 65 hours, it was cooled to room temperature. The reaction mixture was a pale yellow gelatinous mass.

The gel was dissolved in methylene chloride (2 X 50 ml) and washed into a l liter Erlenmeyer flask. After adding 99 percent isopropyl alcohol (300 ml), methyl alcohol (450 ml) was added with vigorous stirring. A fine white precipitate formed, and after 30 minutes, it was filtered and dried.

Yield 5.52 g Yield 5.52 (100) 50% A small sample was heated and emitted a strong menthol-like odor.

Elemental Analysis: Found: C, 71.60: H, l0.54', O, 18.04 Calo: C, 7l.60; H, 10.52; 0, 17.88

Molecular weight determination by the ebulliometric method in dichloromethane gave a value of approximately 2500 (i.e. M 9). Polymers prepared with slight variations in procedure, such as increased catalyst concentration, showed values of about 5000 (M 18) and 7500 (M 25).

EXAMPLE 3 Polymer as Tobacco Flavorant Reconstituted tobacco was prepared as handsheets by a conventional method, with 6.0 percent by weight of the powdered polymer product of Example 2 incorporated in it at the slurry stage. There was no odor of menthol observed during casting, drying, or shredding of the sheets.

The shredded product was mixed with an equal portion of cased commercial filler containing no menthol. Cigarets mm long with 20 mm commercial cellulose acetate filters were prepared from this mixture by use ofa manual cigaret maker. The total weight of filler per Samples of fractions 2, 3, and 4 were submitted for 65 cigaret was 900 mg, containing 27 mg (3.0 percent) of NMR analyses.

Data for NMR indicated that fraction 3 was the desired l-menthyl l,l-dimethylallyl carbonate.

the polymer.

The cigarets were smoked according to the standard FTC method and menthol was found to be present in the mainstream smoke. The puff count was 12.1 and a total 0.59 mg of menthol was measured. The theoretically available menthol was 58 percent of the polymer weight, or 15.7 mg; the amount found in mainstream EXAMPLE Preparation of l-Menthyl l-Benzyl-l-methylbut-B-enyl Carbonate N:1 R:CH R:benzy1 smoke was 3.8 percent of this. Similar cigarets were 5 The method of Grighard and Chambret, P packaged and stored under the various conditions indifehd- 182, 299(1926) was used to P p cated below. Changes in menthol delivery upon smoky p The alcohol was converted to i were d d as not i ifi t the l-menthyl carbonate by a procedure like that of Example 4. Distillation of the extracted product through an 8-inch Vigreux column gave fractions boiling Storage 25-1 10 "/0.040.6 mm, all having strong OH absorption Period Conditions mg/cigaret 1n the infra-red. The residue was distilled through a 7 da 5 Ambient humid mom temperatme 0 45 short path and the fraction boiling 165-6/0.6-0.7 mm lmd nth Ambient humiditgz room temperature 0:53 Showed the followmg IR absorptlonsf no OH Strong lmonth Relative humidity, 110F. 0.59 5 carbonate (1750 and 1255 cm"), vinyl (1655, 978, 1 month 85% Relative humidity 050 913 cm), monosubstituted aromatic (750 shoulder, 697 cm). NMR analysis indicated 80 percent of the Clgarets prepared accordance wlth the example expected mixed ester, a yield of 18.0 percent from the were also Smoked by a P h of expert m who alcohol. This product had very little odor, but on heatfound acceptable to excessive menthol coollng with no m produced a menthol odor off notes.

EXAMPLE 4 EXAMPLE 6 Preparation of l-Menthyl 1,l-Dimethylundec-lO-enyl Preparation of 1 Memhyl 1 Ethy1 l methylpem 4 enyl Carbonate Carbonate N12 R-ethyl R'zmethyl A solution of Z-methyldodec-l 1-en-2-ol (39.70g, Alcohol 0.20 mole) in anhydrous THF (300 ml) was cooled to The Grignard reaction was employed to prepare ice temperature and nitrogen was Passed through the 3-methylhept-6-en-3-ol from 5-hexen-2-one and-ethyl System 20 minutesy lithium M bromide by a conventional procedure. Theidistilled 8116, 120 mole) was added Via a Syringe to the product showed a yield of 77 percent and possessed a cold, stirred solution over a period of 10 minutes. An boilingpoint in the range 67 80C at 20 mm which is evolution Of butane was noted during the addition. The the and pressure given cologne and Clerc lemon yellow solution was then stirred at room temper- Soc hi France, 195 5 836 f hi compound 1R ature for 2 hours. Because the gas evolution had not d NMR d h d a pure product ceased, the solution was warmed to about C and 35 Carbonate held there for 45 minutes. After the solution had been T prepare l-menthyl 1-ethyl-1-methylpent-4-enyl cooled to ice temperature, l-menthyl chloroformate c bonate, a solution of the alcohol (17.6g, 0.137 (45.9g, 0.21 mole) in anhy r THF Was mole) in anhydrous tetrahydrofuran (THF, 100 ml) added over a 9-minute period- T e Color Of the reacwas flushed with nitrogen for 10 minutes and cooled to tion mixture went from lemon-yellow to wine-red. The ice temperature, n-Butyllithium in hexane (0.12 mole, reaction mixture was heated at reflux temperature for 54 ml of 2.34 M soln.) was added by syringe in 2.5 min- 2 hours, was cooled to ice temperature, and Was then utes; there was gas evolution. The mixture was stirred hydrolyzed with 700 ml Water. The aqu l y r Was at room temperature for 1.5 hours and recooled to ice extracted with 4 X 100 ml anhydrous eth The temperature. A solution of l-menthyl chloroformate bined organic layers were filtered and then dried for 16 (210 0,10 l i 75 l anhydrous THF w dd d hours v anhydrous Na SO After filtration, the solin 6 minutes. The pale yellow solution was heated at revents (ether and THF) were stripped from the reaction flux for 2 hours and then recooled to ice temperature. product with the aid of a rotary evaporator. The resi- Th l ti was r f ll h d l d i h 300 ml f due was a deep red, Oily liquid. it was distilled under 16- water, the layers were eparated, and the aqueous layer duced pressure through a 6-inch Vigreux column and was washed with 3 X' ml of ether. The combined four fractions were taken; IR and NMR spectra indiether and organic layers were dried over anhydrous cated that the product was concentrated in fractions 3 Na SO for 17 hours. Filtration and concentration gave and 4, particularly the latter, and probably in the resia liquid residue (35g) which was distilled under redue. (see below) duced pressure through an eight-inch Vigreux column;

Fraction Weight bp (mm) 1R NMR 1 348g 28-85C (O.20.3) strong OH,

no C=O 2 14.85 7787 (0.20.35) strong OH,

no C=O 3 4.3 87-100 1 OH and C=O Estim. 50%

menthol 4 32.35 103117 1 OH and C=O Estim. 35%

menthol Residue Carbonate,

no menthol fraction 2 appeared to be menthol and had to be removed from'the cold finger where it condensed as crystals.

extracted with 4 X 75 ml of ether and the combined organic layers dried 17 hours over anhydrous Na SO Filtering and concentrating gave 37g of liquid product.

Fraction 3 was clear, colorless liquid with a faint non- This was distilled through an eight-inch Vigreux colmenthol'odor; heating caused liberation of a menthollike odor. Yield of the mixed carbonate was 56.2 percent.

EXAMPLE 7 Preparation of l-Menthyl 1-Isopropyl-l-phenylbut-3-enyl Carbonate N11 Rzphenyl Rzisopropyl 2-Methyl-3 -phenylhex-5-en-3-ol Allylmagnesium bromide was prepared by conventional means from allyl bromide (90.75g, 0.75 mole) and the ether solution cooled to ice temperature.

lsobutyrophenone (74.1 g, 0.5 mole) in 200 ml anhydrous ether was added at a rate to maintain gentle reflux, over a period of 100 minutes. The mixture was heated to reflux for about 50 minutes and left at room temperature overnight. It was poured over 500g of ice and a white precipitate formed. This was dissolved by adding 500 ml of percent HCl and the separated aqueous layer was extracted with 4 X 74 ml of ether. The combined organic layers were washed with 3 X 125 ml of 5 percent sodium bicarbonate and 5 X 100 ml of water and dried over anhydrous Na SO four hours. Filtration and concentration gave 84g of liquid which was then distilled through an eight-inch Vigreux column under reduced pressure.

The yield (fraction 5) was 44.4 percent; NMR analysis confirmed it to be the pure alcohol. Carbonate A solution of the alcohol (19.0g, 0.10 mole) in .100 ml of anhydrous THF, flushed with nitrogen, was cooled to ice temperature; n-butyllithium (0.12 mole, 54 ml of 2.34 M in hexane) was added by syringe in six minutes; and gas evolution from the orange mixture was noted. It was stirred 1.5 hoursat room temperature and recooled. A solution of l-menthyl chloroformate (21.9g, 0.1 mole) in 75 ml of anhydrous Tl-lF was added in 6-l/2minutes, followed by 75 ml more THE to maintain fluidity. The suspension was heated at reflux for two hours and became an orange-red solution. It was cooled to ice temperature and hydrolyzed with 300 ml of water added slowly. The aqueous layer was umn; the distillate (bp 2492C at 0.08 to 3mm) had menthol odor and no C=O or absorption in IR. The pot residue was a viscous oil having no menthol odor (except when heated), weak OH and strong C=O,

and CH=CH absorption in IR, as well as for monosubstituted aromatic. An estimation of l-menthyl lisopropyl-l-phenylbut-3-enyl carbonate content of this residue was percent by NMR, or 50 percent yield for 26.7g weight.

EXAMPLE 8 Preparation of l-Menthyl l-Methyl-l-phenylbut-3-enyl Carbonate N21 RzCl-l Rzphenyl 2-Phenylpent-4-en-2-ol was prepared by the procedure of Helferich and Lecher, Ber. 3413, 930(1921); see also German Patent 544,388 (1930), CA. 26, 2466 (1932). Literature gives bp 9l-2C/3 mm and the fraction used here had bp 98-9/10 mm. The IR showed a weak to trace C=O and strong OH.

A solution of this alcohol (16.22g, 0.01 mole) in 150 m1 of anhydrous Tl-lF was degassed with nitrogen and cooled to ice temperature. n-Butyllithium (0.12 mole, 53 ml of 2.38 M in hexane) was added by syringe to the stirred solution in six minutes. A slow evolution of butane was noted. The lemon yellow solution was stirred at room temperature for 1.5 hours and recooled to ice temperature. ml of anhydrous THF containing 1- menthyl chloroformate (21.9g, 0.01 mole) was then added over 10 minutes. The orange mixture was heated at reflux for 2 hours and recooled to ice temperature. It was carefully hydrolyzed with 400 ml of water; the aqueous layer was extracted with 4 X 70 ml of ether and the combined organic layers were dried over anhydrous Na- SO 16 hours. Filtering and concentrating gave 34g of orange-red oil. This was distilled through an 8-inch Vigreux column under reduced pressure, and IR spectra were obtained for the fractions.

Fraction Weight bpC (mm) 1R 1 4.42g 24-47 (0.07) Strong OH, weak C=O 2 5.01 52-81 (0.08-

0.11) Strong OH, med. C=O.

O 010 3 4.11 82-99 (0.7) Med. OH, med. C=O,

1f OCO 4 5.0 99-104 (1.0) Weak OH, strong C=O,

5 4.57 104-120 (1.0) Weak OH, C=O, OCO

Fraction 4 subjected to NMR analysis showed a 45 to 50 percent content of the mixed menthyl methylphenylbutenyl carbonate. Its odor was light and pleasant but non-menthol-like. On heating it gave a menthol odor.

EXAMPLE 9 Preparation of lMenthyl 1,1-Diphenylbut-3-enyl Carbonate N:1 R,R':phenyl The method of Kharasch and Weinhouse, J. Org. Chem. 1, 209(1936) was used to prepare 1,l-diphenylbut-3-en-l-ol. The product boiled at 124C/0.05 mm, while the literature teaches l50-55/3 This alcohol (22.4g, 0.10 mole) in 100 ml anhydrous THF was flushed with nitrogen and cooled to ice temperature. n-Butyllithium (0.12 mole, 54 ml of 2.34 M soln. in hexane) was added by syringe in five minutes. There was gas evolution and the mixture became blood red. It was stirred at room temperature for 1.5 hours and recooled. A solution of l-menthyl chloroformate (21.9g, 0.10 mole) in 75 ml of anhydrous THF was added in 10 minutes. The reaction mixture, now light orange, was heated at reflux for two hours and then cooled to ice temperature.

The mixture was carefully hydrolyzed with 300 ml of water. The aqueous layer was extracted with 4 X 75 ml of ether and the combined organic layers were dried over anhydrous Na SO for 16 hours. Filtration and concentration give 38g of a viscous, odorless oil. Attempted distillation gave a product with menthol odor and strong OH absorbance in the IR, indicating decomposition. The undistilled liquid shoed IR evidence for carbonate, aromatic ring, monosubstituted aromatic ring, vinyl, and plural methyl groupsNMR analysis indicated about 70 percent content of the expected carbonate.

EXAMPLE 10 Preparation of l-Menthyl 1,1-Dimethy1pent-4-enyl Carbonate N:2 R,R': CH

A solution of 2-methylhex-5-en-2-o1 (228g, 0.2 mole) in 400 ml of anhydrous THF was cooled to ice temperature and purged with nitrogen; n-butyllithium (100 ml of 2.38 M in hexane) was added to the stirred solution by syringe in 10 minutes. It was stirred at room temperature for 1.5 hours, by which time the evolution of butane had ceased. A solution of 43.8g, 0.2 mole of l-menthyl chloroformate in 150 ml anhydrous THF was added at ice temperature during 1 1.5 minutes.

Calc. found EXAMPLE 1 1 Polymerization The carbonate produced in Example 4, l-menthyl 1,l-dimethylundec-lO-enyl carbonate, after further distillation at 0.5 mm pressure (weight 2.0g) was mixed with 0.2g of benzoyl peroxide and treated according to the procedure of Example 2. Heating time was 96 hours. A colorless, viscous oil was obtained. When 50 ml of methanol was added and the mixture was triturated, a white oily mass settlediout A sample of this 0 mass was subjected to IR analysis; peaks characteristic of carbonate were present at v1740 and 1260 cm", while peaks characteristic of unsaturationat 1640, 1000, and 910 cm" were greatly diminished in comparison with the monomer. After 5 washings i h meth;

anol the oily mass became more tacky but not firmly solid. Heating the odorless material liberated a menthol odor.

Elemental analysis showed:

Calc. found %c 75.74 75.90 11 11.65

Molecular weight, osometric method in acetone, was 1750.

EXAMPLE 1 2 Polymerization The carbonate produced in Example 6, fraction 3, was placed (2.0g) with 015g of benzoyl peroxide in a 100 ml flask and treated as in Example 2, heating for l 12 hours. A colorless, very viscous material was produced. This was dissolved in 40 ml of methylene chloride, and 60 ml of isopropanol was added, then 200 ml of methanol. A white precipitate formed which was tacky and odorless;'on standing this lost its tackiness; its weight was 0.4g. A small sample when heated liberated a strong odor of menthol.

NMR spectrum of this product was consistent with a polymer structure; no evidence of unsaturation appeared. Similarly, IR examination showed that the bands indicative of unsaturation at 1642 cm, 993 cm, and 903" cm were notidistinguishable.

Elemental analysis showed:

Calc. found C 73.50 73.15 H 1 1.04 10.96

Molecular weight, osometric method in acetone, was 1730 (ave. degree of polymerization 5.6).

EXAMPLE l3 Polymerization A heavy-walled glass polymerization vessel was charged with the product of Example 10, l-menthyl 1,1-dimethylpent-4-enyl carbonate, and with benzoyl peroxide. The vessel was purged of air by the freezethaw technique and sealed off under vacuum. in this way, 4.5g of the carbonate was mixed with 300 mg of dure was carried through five cycles and yielded a tacky, transparent, odorless material. After heating to 90 at 1 mm for one hour, polymer weighing 0.75g was retained for testing.

Elemental analysis gave, C,H,O values of 72.45, 10.82, and 16.95, the theoretical values being 72.93, 10.88, and 16.19. Infrared analysis showed the material to contain only a small amount of unsaturation. The number average molecular weight was determined from vapor-phase osometry was 1240 corresponding roughly to tetramer. The 0.75g of purified polymer represented a 17 percent conversion from monomer. However, some polymer was lost during the methanol decantation steps.

What is claimed is:

l. A compound having the chemical formula:

2 R I i H u -o-c-o-c- (c11 cn 2 \c l I I R cu /CH\ l 2 wherein each N has a value of from 0 to 8 and each R and R are selected from the group consisting of alkyl having from 1 t0 6 carbons, cycloalkyl having from 5 to 10 carbons and aromatic carbocyclic having from 6 to 10 carbons.

7. The compound of claim 6, wherein the molecular weight is between about 1600 and 12,000.

-8. The compound of claim 7, wherein each N has a value of from 0 to 2.

9. A menthol-release agent consisting of a homopolymer of l-Menthyl l,l-dimethylallyl carbonate having an average molecular weight of from about 1600 to about 12,000.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,887,603

DATED 1 June 3, 1975 INVENTOR(S) ERIC o.s. RUNDBERG, JR., et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract, the formula should be:

-O-f|-O-T (CH CH-CH wherein:

N O to 8 R and R are independently selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons Column 2, line 5, "the" should read that,

UNITED STATES PATENT OFFICE Page 2 CERTIFICATE OF CORRECTION PATENT NO. 3,887,603 DATED 1 June 3, 1975 NVENTOR S 1 ERIC G.S. RUNDBERG, JR., et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: Q Column 2, Formula (A) should be:

CH M

I wherein: N 01108 M 2 to 100 -and- R and R for each unit are c selected from the group consisting of aliphatic,

alicyclic and aromatic hydrocarbons Column 2, lines 61 and 62, "l-menthyl" should read -menthyl--.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Page 3 PATENT NO. 1 3,887,603 I DATED 1 June 3, 1975 |NVENTOR(5) ERIC G.S. RUNDBERG, JR., et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Q Column 4, line 39, "per se" should read er se--.

Column 4, line 47, capital N should read --"N"--.

Column 5, Formula (1) should be:

0H (3001 O-C-Cl Colurm'l 5, lines 65 and 66, "mentholrelease" should q read --menthol release--.

Column 6, lines 4 and 5, "l-menthyl" should read l -menthyl-- d Column 6, line 7, "l-menthyl" should read l -menthyl-.

UNITED STATES PATENT OFFICE Page 4 CERTIFICATE OF coRREcTTnN PATENT NO. 3,887,603 0 DATED June 3, 1975 lNVENTOR(S) 1 ERIC G.S. RUNDBERG, JR., et al It is certified that error appears in the ab0ve-identified patent and that said Letters Patent are hereby corrected as shown below: Column 7, line 34, "n-Butyllithium" should read n-Butyllithium- Column 7, line 39, "l-menthyl" should read -menthyl-e Column 7, in the Table in Example 1, (5th column), "no" in all three occurrences should read "5 Column 7, line 67, "for NMR" should read -==from NMR- Column 8, line 11, "l-menthyl" should read menthy1--,

0 Column 8, line 15, "minutes" should read --mJ' nute--.

Column 9, line 24, "l-Menthyl" should read l --l- Ienthylo Column 9, line 29, "n-Butyllithium" should read n -Butyllithiu Column 9, line 37, "l-menthyl" should read l menthyl-n Column 10, line 3, "l-Menthyl" should read --l -=-Menthyl-.

Column 10, line 5, "182" should read 182",

UNITED STATES PATENT OFFICE Page 5 CERTIFICATE OF CORRECTION PATENT NO. 1 3,887,603

. DATED June 3, 1975 |NVENTOR(5) ERIC G.S.RUNDBERG, JR., et al it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Column 10, line 8, "l-menthyl" should read -menthyl-.

Column 10, line 24, "l-Menthyl" should read Menthyl--.

Column 10, line 25, "R-ethyl" should read -R:ethyl--.

' Column 10, line 26, "Alcohol" should read -Alcohol--.

Column 10, line 32, "cologne" should read Cologne--.

Column 10, line 35, "Carbonate" should read --Carbonate-.

Column 10, line 44, "l-menthyl" should read l -menthyl--.

Column 11, line 25, "2-Methyl-3-phenylhex-5en-3-ol" should read --2-Methyl-3-phenylhex-5en-3-ol.

Column ll, line 55, "Carbonate" should read --Carbonate--.

Column 11, line 58, "n-butyllithium" should read n-butyllithium--. Column ll, line 62, "l-menthyl" should read l-menthyl a UNITED STATES PATENT OFFICE Page 6 CERTIFICATE OF CORRECTION PATENT NO. 3,887,603 0 DATED June 3, 1975 INVENTOR(S) ERIC G.S. RUNDBERG, JR. et a1 it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown beiow:

Q Column 12, line 34, "l-menthyl" should read -menthyl--.

Column 12, line 41, "l-Menthyl" should read l -Menthyl--.

Column 12, line 45, "34B" should read i I--.

. Column 12, line 46, "26" should read "22-".

Column 12, line 52, "n-Butyllithium" should read "-2- Butyllithium- Column 12, lines 58 and 59, "l-menthyl" should read --l -menthyl-- Column 13, line 24, "l Menthyl" should read l Menthyl--.

0 Column 13, line 27, "Chem. 1," should read --Chem. l,--.

Column 13, line 34, "n-Butyllithium" should read r 1 -Butyllithium-- 0 Column 13, line 38, "l-menthyl" should read --1. -menthyl--.

Column 13, line 58, "l-Menthyl" should read l -Menthyl--.

Column 13, line 62, "n-butyllithium" should read -butyllithium-- UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Page 7 PATENT NO. 3,8

DATED 1 June 3, 1975 INVENTOR(S) ERIC 5, RUNDBERG, JR., et 511 It is certified that error appears in the ahove-identified patent and that said Letters Patent are hereby corrected as shown below:

W Column 13, line 66, "l-menthyl" should read -l-menthyl--.

Column 14, line 23, "l-menthyl" should read "l-menthyl".

Column 15, line 12, "l-menthyl" should read l -menthyl-.

Column 15, line 68, "monomerrich" should read 7 --monomer rich--.

Column 16, line 5, gave, C,H,O" should read --gave C,H,0--.

Column 16, line 9, "was" should read --as-.

Q Column 17, claim 5, "compound of claim 5" should read "compound of claim 4".

Column 18, claim 9, "l-Menthyl" should read "l-menthyl".

Signed and Sealed this third Day of February 1976 [SEAL] 7 Attest:

RUTH C. MASON C. MARSHALL DANN 14119511718 ff Commissioner oj'PaIents and Trademarks 

1. A COMPOUND HAVING THE CHEMICAL FORMULA:
 1. A compound having the chemical formula:
 2. The compound of claim 1, wherein N, N2 and each N1 have values of from 0 to
 2. 3. The compound of claim 2, wherein N, N2 and each N1 have values of
 0. 4. The compound of claim 2, wherein M has a value of from 4 to
 38. 5. The compound of claim 5, wherein N, N2 and each N1 l have values of
 0. 6. A compound having a molecular weight between about 550 and about 30,000 and consisting essentially of polymeric units of the formula:
 7. The compound of claim 6, wherein the molecular weight is between about 1600 and 12,000.
 8. The compound of claim 7, wherein each N has a value of from 0 to
 2. 